LONDON -- Western intelligence has begun to detect tension within the Iranian regime over the country’s nuclear program, officials told NBC News on Friday.

Even so, the European Union on Friday provisionally approved substantial new economic sanctions against Tehran.

The new sanctions will have to be formally approved on Monday at an EU foreign ministers' meeting in Luxembourg before coming into effect.

The sanctions, aimed at trying to change policy in Tehran, will target areas such as shipping, banking and trade in parts that could be used to build a nuclear weapon. Measures already in place include an oil embargo that is causing serious economic woes and leading to protests on the streets.

Tehran denies its nuclear work has any military intentions and says it wants nuclear power for electricity supplies and medical needs.

Despite stalled talks between Iran and a six-country alliance of Western powers, including the United States, a Western diplomatic source said contact with Iranian officials has been sustained consistently, including during the months since the summer.

Western official: 'Tension within the Iranian regime'The official told NBC News there are some signs of “tension within the Iranian regime” over the issue.

"We’ve picked up some small signs of wavering on the nuclear policy," the official, who did not want to be named, said. "But I don’t want to exaggerate it."

He added that so far there is “no sign Iran is prepared to move” making renewed sanctions necessary.

Any change in policy from either side is only likely to emerge after the U.S. presidential election: If Iran is prepared to negotiate, it will want to know whether it is talking to an Obama administration or a Romney administration.

He warned that if Iran is able to attain nuclear weapons it could “trigger a nuclear arms race in the Middle East.”

In this assertion, Ryan appeared closer to Israeli Prime Minister Benjamin Netanyahu, who dramatically told the United Nations in September that Israel was drawing a “red line” for Iran’s nuclear program and claimed the country could be on the brink of a nuclear weapon in less than a year.

In an attempt to convey what he sees as a threat to Israel's existence, Israel's Prime Minister Benjamin Netanyahu used a cartoon to illustrate how close he says Iran is to developing a nuclear weapon. In a speech at the United Nations General Assembly he asked the world to help stop them. NBC's Andrea Mitchell reports.

EU steps up pressureOn Friday, the Western official said the chief purpose of the sanctions is to “slow down Iran’s nuclear program” and that the aim is not to target the Iranian people.

The trade and finance measures mark a major step-up of European pressure on Tehran, amid growing concerns over its nuclear program, foundering diplomacy and threats of attack on Iranian installations by Israel.

The EU is also targeting Iran's shipping industry, in an effort to curb Tehran's ability to sell oil to obtain funds and hard currency. It banned imports of Iranian oil earlier this year.